In general, a refrigerator is an apparatus in which cold air, generated via a refrigeration cycle including a compressor, a condenser, an expansion valve, an evaporator, etc., is supplied into a storage compartment to keep food stored in the storage compartment at freezing or at a temperature slightly above freezing.
A typical refrigerator internally defines two storage compartments including a freezing compartment in which foods or beverages are kept frozen and a refrigerating compartment in which foods or beverages are kept cold, but not frozen.
There are several kinds of refrigerators including a top mounting type refrigerator in which a freezing compartment is located above a refrigerating compartment, a bottom freezer type refrigerator in which a freezing compartment is located below a refrigerating compartment, and a side by side type refrigerator in which a freezing compartment and a refrigerating compartment are divided into left and right sides.
Among the aforementioned storage compartments of the refrigerator, the refrigerating compartment may receive food to be stored at a temperature of 0-5° C. Foods for storage at such a temperature slightly above freezing comprise various kinds of foods, such as vegetables, fruits, various side dishes, water, beverages, etc.
For example, milk, which may be frequently used, is stored in the refrigerating compartment. Milk may be stored on a shelf or a door basket of the refrigerating compartment.